Remove trim, marker lights, bumpers, etc...Take a good look at the car and the replacement parts it will require. You need to know exactly what needs to get cut off and what doesn't. For example, the gutter that holds the trunk weather stripping isn't part of the factory quarter; GM offered this as a separate piece. The Goodmark quarter is manufactured like the original, so keep the gutter. If you whack it off, you're going to have to put it back on. Know what you are doing before you start to save yourself grief.